Many aerospace and other pump applications require a vane or gerotor type positive displacement cartridge style pump to be installed in the housing of an application component such as a generator, gearbox, engine or other application component or system for moving oil, fuel, coolant or other fluid through the component or system. Existing cartridge pumps have an integral pump housing that contains all of the pump elements and drive components. Gaps or clearances between components and housings result in a reduction of the pump volumetric efficiency as leakage will occur from higher pressure to lower pressure areas of the pump and system. The two main considerations for leakage are from the discharge to the inlet of each pumping element and from one pumping element to another pumping element when multiple elements exist within one pump. Critical clearances that directly affect the pump volumetric efficiency are the clearance between the pump housing outer diameter and application housing (generator, gearbox, etc.), and the pump housing inner diameter and pumping components.